John949

I don't think it's the thickness of a sail that's the issue, it's the flexibility of the material that matters. Of course thickness is much easier to measure but it's hard to come up with a good rule that is based on measuring the wrong parameter. If rule changes are being considered then we should also look at the term 'soft sail'. From an engineering standpoint, softness (cf hardness) is the resistance of the material to compression, not how easily it bends. For example, sponge rubber is soft, diamond is hard. If we do want to limit the stiffness of sails then the rule should state what the maximum bending stiffness should be. Many years ago (40 odd?) a read an article on the development of padded sails i.e. two sails with a thin layer of shaped foam between them. I don't think the idea worked but it is interesting to consider whether such a sail could be described as soft, it would certainly be described as thick. It's also intersting to note tht the idea has re-surfaced (in a slightly different form) on the current AC75s.

Does their GPS software not do position prediction and therefore tell them if they can cross safely? I'm all in favour of innovation in sailing but we need to be careful that sailing doesn't become a contest in software writing rather than human skill.

I watch it with the sound off and FF to about two minutes before the start because I find the commentary so banal, but each to his own. If you have Sky or Virgin then it's worth recording both the live and the replay versions as they frequently get delays and the live version can finish before the race does. The boat designs are interesting from a safety point of view as half the crew would be underwater in the normal capsized position. Let's hope there isn't anything for their clothing or safety lines to snag on.

Thought I'd have a go at sailmaking but I'm a bit confused by a couple of points in the rules. 1) Width Measurement. The sail measurement diagrams show that the 'widths' are measured between the 1/4, 1/2 & 3/4 points on the leech and the nearest point on the luff. Simple enough but how do you find the 1/4, 1/2 & 3/4 points on the leech? Since the leech has a significant curve, do you have to measure round this curve, as that is a difficult to do in advance. 2) Leech Radius. The wording of J.6 is confusing to me. I think it's saying that you can have angles (or radii less than 900mm) in the leech, as long as they occur at either the leech points or at batten points. Or put anther way, one could have a sail with the 1/4, 1/2, 3/4 widths all the same. The sail would effectively be a quadrilateral with a right angled triangle on top. Obviously not a great idea but there is clearly a temptation to increase the width of the upper part of the sail for light airs.